It has been reported that the software running Apple‘s iPhones, iPads and the iPod Touch has “critical weaknesses” that could be used by criminals to gain access to confidential data on the devices, Germany’s IT security agency has warned.

Clicking on an infected PDF file “is sufficient to infect the mobile device with malware without the user’s knowledge” on several versions of Apple’s iOS operating system.

The problem may occur on iPhone 3GS, iPhone 4, iPad, iPad 2 and the iPod Touch with software versions including iOS 4.3.3.

The problem can occur when opening a website that carries an infected PDF file, possibly allowing criminals to spy on passwords, planners, photos, text messages, emails and even listen in on phone conversations.

“The weak points allow possible attackers to gain administrator rights and get access to the entire system,” the bureau said. Apple has not yet issued a fix for the problem.

But until Apple works out how to fix the vulnerability and issues a software patch, jailbroken phones are more secure than the huge majority out there.

“If things turn bad and we see an iPhone outbreak via the new PDF vulnerability, there’s not much you can do,” said Mikko Hypponen of the security company F-Secure. “There are no antiviruses available on the iPhone.”